Metal scrap packages and methods and apparatus capable of being used therewith

ABSTRACT

The present invention relates to a material package comprising a housing, at least one piece of scrap material contained in the housing, wherein the weight of the housing is from 1 to 5% of the weight of said scrap material, and the housing and the scrap material have melting points that are greater than about 300° F. The present invention further relates to associated methods and products employed with material packages as well as meltable housings, per se.

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field of the Invention

[0002] The present invention relates generally to metal scrap andassociated methods, and in particular, to methods suitable for use withAl—Li scrap as well as associated apparatus and products producedthereby.

[0003] 2.. Description of Related Art

[0004] With the large volume of products made of metal worldwide, thereis inevitably an issue about what to do with the huge quantities ofscrap metal that is left over after many manufacturing and machiningoperations. The scrap metal produced from these operations varies insize from small machined chips or swarf to various sized solid remnant.Moreover, since many metal alloys are constantly being reengineered anddeveloped, large quantities of alloy scrap are often generated for everypound of usable metal produced. For example, a typical aircraft partmachined from plate may have a “start-to-finish” ratio (the ratio of thestarting raw stock weight to the finished part weight) of between 10 to120 lbs of starting raw material weight for every pound of finishedweight. This is particularly the case with respect to aluminum lithiummetal alloys that are very lightweight and are still in many cases, inthe experimental stage. Furthermore prior attempts recovering scrapAl—Li have been limited to large scrap that is produced during themanufacturing process at the mill, i.e., ingot heads and ingot butts.Solid Al—Li scrap material must be placed in the induction furnacequickly and carefully to avoid damaging the furnace linings. Thus, Al—Liof small sizes cannot be successfully recycled at all due to theseproblems, and hence, often goes to waste.

[0005] With respect to aluminum lithium and other alloys, it has beenproposed in the past according, for example, to U.S. Pat. Nos. 4,882,017and 4,973,390 to employ an electrolytic cell to extract lithium from thescrap, apparently in an effort to separate the alloying elements andreuse them individually. Further, with respect to other metals andalloys, other recycling methodologies have been suggested such as inU.S. Pat. Nos. 5,032,171, 6,074,455, 6,273,932 and 5,167,700. In theseand related processes, various mechanisms for remelting and/orreincorporating scrap metal alloys are described. However, none of themethods proposed heretofore has provided a reliable and simple mechanismthat can be used in any shop or facility that enables storage andseparation of particular metal alloys.

SUMMARY OF THE INVENTION

[0006] It was therefore an object of the present invention to provide amethod for recycling and/or incorporating metal alloys such as aluminumlithium alloys of virtually any size. Since most of the scrap materialfrom machine shops is small, i.e., various shapes ranging from 1 poundto 200 pounds each, a method has been proposed capable of packagingscrap such that it could be loaded as a large quantity as quickly aspossible.

[0007] In accordance with these and other objects, there is provided ameltable housing capable of receivingly accepting at least one metalalloy therein. The meltable housing preferably has a melting point lowerthan the casting temperature of the metal alloy sought to be containedtherein. That is, the meltable housing preferably has a melting pointthat is high enough to maintain sufficient structural integrity to holdthe weight of metal alloy scrap during elevated temperature dryingoperations and during insertion into the casting furnace.

[0008] In one embodiment, the meltable housing forms a mesh “basket”with at least one entryway provided therein such that metal to berecycled can be placed therein. The mesh basket for melting aluminumlithium alloys can be made, for example, of 3003 or any suitablematerial that may be desired for a particular type of alloy.

[0009] The present invention is further directed to methods of recyclingmetal as well as to metal packages and products formed thereby.

[0010] Additional objects, features and advantages of the invention willbe set forth in the description which follows, and in part, will beobvious from the description, or may be learned by practice of theinvention. The objects, features and advantages of the invention may berealized and obtained by means of the instrumentalities and combinationparticularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a layout of a mesh basket prior to assembly according toone embodiment of the present invention.

[0012]FIG. 2 is a side view of a mesh basket manufactured according toone embodiment of the present invention.

[0013]FIG. 3 is a top view of a basket of FIG. 2.

[0014]FIG. 4 is a close up view of a portion of FIG. 2 showing how meshcould be designed according to one embodiment of the present invention.

[0015]FIG. 5 is an assembled view of a mesh basket showing metal scraploaded therein.

[0016]FIG. 6 is a graph representing percent savings capable beingachieved compared with virgin material according to one embodiment ofthe present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0017] Since most scrap material from machine shops is small, i.e.,various shapes ranging from 1 pound to 200 pounds each, a method wasneeded to package the scrap such that it could be loaded as a largequantity (i.e. quantities ranging from 1000 to 4000 pounds, preferablyfrom 2500 to 3500 pounds) as quickly and easily as possible. Inconnection with the present invention, there is provided a meltablebasket, preferably formed of metal such as aluminum alloy AA 3003 meshmaterial. However, the composition of the housing does not necessarilyhave to comprise aluminum, but actually can be fabricated in any desiredcomposition or shape depending on the material sought to be packagedtherein. In one embodiment, the metal basket is formed into arectangular basket. See FIGS. 1-5. The meltable housing can be formed ofany commercially available product and preferably has a melting pointlower than the casting temperature of the metal alloy contained thereinthat is sought to be recycled. For example, a meltable housing made ofAA 3003 would have a solidus temperature of approximately 1190° F. and aliquidus temperature of approximately 1210° F. The meltable housing insuch an embodiment would melt at a temperature below the castingtemperature for aluminum lithium alloys. 3003 also has sufficientstrength at temperatures between room temperature and the meltingtemperature of Al—Li to hold the weight of the metal alloy contained inthe housing when subjected to elevated temperature drying operations andduring insertion into the casting furnace.

[0018] In one embodiment as shown in FIG. 1, two pieces of mesh metal 10that melts at a temperature below the casting temperature of the metalalloy contained therein, for example between 1190 and 1210° F. withrespect to Al—Li, is formed into rectangular shape of any desired sizeA×B×C, whereby A is the width, B is the height, and C is the length. Inone embodiment, the rectangular shape is 30″×60″×30″ corresponding to avolume consistent with the furnace capabilities and loading methods.FIG. 1 shows the forming locations 70 where the mesh metal is bent toform the rectangular shape. The formed parts are placed 90° with respectto each other as shown in FIG. 2 and FIG. 3 to form a rectangular basket20 that has a double thick bottom 80 and top with dimensions of A×C″ andsides of B×C″. The sides are interlocked together (see FIG. 4) and canbe wired together by any desired means, such as with aluminum wire 40,50. The mesh in the basket is preferably of a size having openingsranging from 0.04″ to 2″, and more preferably has diamond shaped meshopening sizes ranging from 0.7″ to 1.5″. By having mesh that isrelatively small as described above, a machine shop is then able to loadthe baskets with small sized scrap metal 30. As shown for example inFIG. 4, an exploded close up view of an advantageous design of mesh isshown. The sheets are secured using any desired mechanism. In apreferred embodiment, the edges of the sheets 10 are bent in aparticular fashion as shown, for example in FIG. 4. The edges of thesheets 10 alternates in a “bend up” 40 “bend down” 50 orientation atangles 60 preferably ranging from 45° to 170°, more preferably from 80°to 110°. The edges shown in FIG. 4 are shown prior to bending tointerlock the edges together. Note that it is also possible to form ahousing that is not mesh but designed to fully contain a quantity ofmetal sought to be recycled. The overlapping edges of the sheets 40, 50are shown in FIG. 4 is advantageous because the sheets 10 are able to beintermeshed to form a strong joint without necessarily requiring wiresor other fasteners. In addition, the interlocking is preferably orientedin the depicted “bend up” “bend down” configuration because it minimizesthe use of other alloy additions such as aluminum wire to the melt.

[0019] In one embodiment the gauge of the material forming the basket orhousing is advantageously from 0.10″ to 0.31″ and when formed into abasket, can house about 3500 lbs of scrap. In one embodiment, the gaugeis about 0.11.″ However, the gauge can be adjusted higher or lowerdepending on the requirements of the particular product being recycledand remelted.

[0020] A metal package housed as described above, is advantageous inthat it can easily be lifted and moved with a common forklift andhoisted into a truck or other trailer or railway car for removal andtransport to be remelted.

[0021] With respect to aluminum lithium alloys, the mesh design isparticularly advantageous because the scrap material can be cleanedand/or dried after it is packaged. Once the housing or basket is full,the metal to be remelted can be dried at any suitable temperature, suchas at a temperature from about 100° to 350° F. to remove water, oils andcontaminates. The housing or basket can also be immersed or sprayed witha cleaning solution or suitable solvent to remove oils and contaminatesprior to drying at elevated temperatures. The drying temperature shouldadvantageously be lower than the melting temperature housing or themetal contained therein. The weight of the housing is preferably from 1%to 5% , more preferably from 2% to 3% of the weight of the material tobe contained therein. These weight ratios are desirable because theyminimize any undesirable alloy additions that may be present in thecommercial metal basket materials. With respect to housing made of 3003,such an alloy has a higher iron level than many aluminum lithium alloys.The low weight ratio of the housing alloy to the weight of the aluminumlithium dilutes the iron levels close to the level of the aluminumlithium. The total material package generally has a weight that ispreferably less than 3500 lbs. in order to ensure transportabilitythereof.

[0022] Once the housing 20 is loaded with a desired amount of scrap orother material to be housed, a “material package” is formed. In oneembodiment, for example as shown in FIG. 5, the material package 20comprises a mesh basket comprising at least one piece of metal 30therein. When the material package 20 is sought to be melted, one ormore material packages are delivered into a furnace (not shown) such asan Al—Li furnace to preferably provide for at least a 25% charge. Interms of Al—Li materials and other alloys where one or more of thealloying elements is relatively expensive, employing at least a 50%charge may reduce the need for Li and other expensive alloying elementsand reduces the cost of the metal by up to 200% in some cases. Thereduction in cost is possible without sacrificing any properties of theunderlying material since the scrap being recycled is preferably of theidentical composition as the materials being generated and formed intoingots.

[0023] Aluminum-Lithium solid remnant or compressed swarf/chips areparticularly difficult to recycle from end-users such as machine shopsbecause the remnant sizes are small (from 1 to 200 pounds) and difficultto load quickly and safely into the induction furnace. Methods to jointhe scrap together such as steel banding, welding, or other methods arenot easily accomplished or introduce undesirable alloying elements intothe furnace. The instant method and material package provides anaffordable way for machine shops and other end-users to package thesolid remnant or compressed swarf/chips into a container that ispreferably capable of being melted along with the remnant material. Thismethod is suitable for virtually any conventional aluminum alloysincluding Al—Li alloys as well as any other metal or product that needsto be recovered and returned to use with virgin material. Othermaterials capable of employing the instant material package and methodinclude steel remnants, magnesium metals, copper alloys, titaniumalloys, nickel alloys, thermoplastic materials, and polymers. Thehousing 10 to be used with materials other than aluminum will be formedof a material having a melting point that is similar to the meltingpoint of the material(s) sought to be recycled. As such, the meltingpoint of housings for materials other than aluminum alloys may not havemelting points from 1190° to 1210° F. as described above with respect toaluminum materials, but rather, will be chosen to optimize the meltingand remelting of the material package being treated.

[0024] It is anticipated that end-users would be able to use the basketsas a normal part of their manufacturing process, thus reducing theiroverall scrap handling issues and providing an easy method ofsegregating solid scrap by alloy. In addition, in accordance withanother embodiment of the present invention, such a meltable housing canbe used to create new alloys by introducing two or more differentmaterials therein and subjecting the filled housing to a temperaturesufficient to melt the housing and the contents so as to form a finalproduct. In some embodiments, the housing and the materials sought to bemelted therein will have melting temperatures greater than 300° F.

[0025] Other types of baskets or packages could alternatively beemployed such as wrapping the scrap in remeltable sheet or meshcontainers. Automated processes or machines that would package the scrapin such a manner could also be utilized if desired for any reason.

EXAMPLES Example 1

[0026] Container and Method Description:

[0027] An aluminum 3003 expanded mesh sheet was formed into arectangular basket and wired together using 6063 aluminum wire. For anAl—Li furnace, a basket having dimensions of 30″×30″×60″ was producedand filled with 3000 lbs. of remnant Al—Li material having sizedimensions ranging from 1 to 2000 cubic inches. The package was securedusing 6063 aluminum wire, and shipped to the cast house. The basketcontained approximately 3000 lbs of solid remnant with a wire basketweight of about 46 lbs. In this example, the weight ratio between the3003 basket and remnant material was 1.5% and this ratio allowed fordilution of any undesirable alloy elements such as Fe in the 3003 basketmaterial. The filled basket was heated to a temperature of 250° F. thatwas suitable to off-gas any moisture or other contaminates prior tolowering into the induction furnace. A typical range for such heatingcould be between 100° F. and 500° F. After heating to removecontaminates, the scrap basket was lowered into a remelt furnace astypically done with large scrap pieces.

Example 2

[0028] According to Example 2, the following materials were prepared asset forth below:

[0029] 100% virgin aluminum standard ingot (no baskets)

[0030] 60% virgin aluminum ingot+40% scrap (Two 2500 lb baskets)

[0031] 20% virgin aluminum ingot+80% scrap (Four 2500 lb baskets)

[0032] The material employed was aluminum mesh—2 pieces 0.125″thick×30″×210″ to produce a form. The form was broken at the locations70 as shown in FIG. 2 and sheets 10 were combined together using thecenter section 80 as a “double bottom” to provide additional strength.The basket was filled with solid scrap and compressed chips, segregatedby alloy. The top of the basket 20 was closed and the edges wereinterwoven with the sides of the basket as shown in FIG. 4. The basketwas shipped to a casting facility with the basket labeled with the nameof the alloy. The basket was heated in an air furnace to above 250° F.to remove water and oils that may have been on the surface of scrap andthis temperature was held for a time commensurate with the level ofcontamination to ensure removal of contaminates based on condition ofscrap. The induction furnace was loaded with the scrap containingbaskets and the remaining void was filled with virgin metal. The loadwas melted and cast according to known techniques. The baskets meltedalong with scrap and virgin material.

[0033]FIG. 6 illustrates certain cost reductions possible through theutilization of one or more scrap baskets in a casting operationaccording to one embodiment of the present invention as exemplified inExample 2. FIG. 6 compares the use of 100% virgin metals, alloyingelements, and hardeners (A), 40% scrap/60% virgin metals (B), and 80%scrap/20% virgin metals (C) according to the results reported in Example2. The use of one (B) or two (C) scrap containers has been demonstratedto reduce the metal cost associated with casting operations from 22 to44% over the use of 100% virgin materials (A). The left hand side ofFIG. 6 shows the potential cost savings versus 100% virgin metal.

[0034] Additional advantages, features and modifications will readilyoccur to those skilled in the art. Therefore, the invention in itsbroader aspects is not limited to the specific details, andrepresentative devices, shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

[0035] All documents referred to herein are specifically incorporatedherein by reference in their entireties.

[0036] As used herein and in the following claims, articles such as“the”, “a” and “an” can connote the singular or plural.

What is claimed is:
 1. A material package comprising: a housing, atleast one piece of scrap material contained in said housing, wherein theweight of said housing is from 1 to 5% of the weight of said scrapmaterial, and said housing and said scrap material have melting pointsthat are greater than 300° F.
 2. A material package according to claim1, wherein said housing comprises a mesh basket.
 3. A material packageaccording to claim 2, wherein said mesh basket comprises aluminum.
 4. Amaterial package according to claim 2, wherein said scrap materialcomprises aluminum.
 5. A material package according to claim 2, whereinboth said scrap material and said mesh basket comprise aluminum.
 6. Amaterial package according to claim 5, wherein said scrap materialcomprises Al—Li.
 7. A method for recycling scrap material comprisingloading said scrap material in a housing, optionally drying said scrapmaterial and said housing to remove residual contaminates and/ormoisture, optionally loading virgin material having a composition thatis substantially the same as said scrap material into said housing, andsubjecting said scrap material and said housing to a treatmentsufficient to melt said scrap material and said housing.
 8. A methodaccording to claim 7, wherein said housing comprises a mesh basket.
 9. Amethod according to claim 8, wherein said mesh basket comprisesaluminum.
 10. A method according to claim 8, wherein said scrap materialcomprises aluminum.
 11. A method according to claim 8, wherein both saidscrap material and said mesh basket comprise aluminum.
 12. A methodaccording to claim 11, wherein said scrap material comprises Al—Li. 13.An aluminum alloy wherein at least 5% thereof was prepared from amaterial package according to claim
 1. 14. An aluminum alloy comprisingrecycled material, wherein said aluminum alloy was prepared according toa method of claim
 7. 15. A housing capable of recycling metal comprisingtwo sheets, optionally formed of mesh, said sheets being transposed withrespect to each other to form a basket structure, wherein edges of saidsheets are interwoven at an angle ranging from 80 to 110 degrees.
 16. Amaterial package comprising a housing according to claim 15 and scrapmaterial therein.
 17. A housing according to claim 15 comprisingaluminum alloy AA 3003 mesh material.
 18. A material package accordingto claim 16, wherein said scrap material comprises aluminum.
 19. Amaterial package according to claim 18, wherein said scrap materialcomprises aluminum lithium.
 20. A material package according to claim 1,wherein the gauge of said housing is about 0.11.
 21. A method forforming an alloy comprising placing at least two different materials ina meltable housing and subjecting the housing containing said materialsto a temperature sufficient to melt said housing and said materials.